Water is an important source and auxiliary material in the production of cosmetic and pharmaceutical products. It also serves as a rinsing aid for CIP cleaning of the product-contacting surfaces of the plant components and the pipelines. Water systems are therefore among the key systems in the production process of products.
The different branches of industry have different water requirements.
General terms for water qualities:
- DI - Water (fully demineralised / deionised water
- WFI - Water for Injection
- PW - Purified Water
- HPW - Highly Purified Water
The level of purity of demineralised water is mostly determined by measuring the electrical conductivity of the water µS/cm, by means of conductivity measuring devices.
Mode of operation of generating water using the reverse osmosis procedure
Reverse osmosis is used to substantially remove dissolved components of the available raw water. In the case of high calcium content in the raw water, the use of an upstream softening plant is recommended. All water treatment plants start with a filtration stage: Multi-level filters, candle filters (with depth effect) or, more recently, ultrafiltration and microfiltration systems are used in the case of particulate pollution or turbidity. After this first purification step, a number of further processes are available with which certain water constituents can be removed. By means of active carbon filters, for example, oxidization agents can be reduced or low molecular organic impurities can be absorbed and thus removed from the water.
In a softening plant, calcium (Ca2+) and magnesium (Mg2+) or also metals like bivalent iron are replaced by sodium ions (Na+). With the large inner surface of the resin bed, softening is the most microbiologically critical element of the entire processing chain. Chemical disinfection during the regeneration keeps the germ counts at a tolerable level. Today, plants which are can be sanitised with hot water are increasingly being given preference. In modern water treatment plants, reverse osmosis is the process of choice for desalinisation. This can be attributed to the numerous advantages over ion exchangers. Reverse osmosis, a membrane process, is both a mechanical and chemical filtration process. In this process, the feed water is forced through the semi-permeable membrane at a higher pressure than the osmotic pressure and thereby divided into a concentrate flow containing the separated salts and other impurities and a permeate flow (pure water with a very low salt content). The membranes of reverse osmosis are extremely sensitive to fouling, scaling and oxidization agents. With reverse osmosis, excellent separation rates for salts, particles, micro-organisms, pyrogens and other ingredients can be achieved. In order to achieve the required conductivity of the pure water, a second stage or an electro-deionisation plant /EDI) is connected downstream, which provides a lower residual salt content and thus an improved safety margin to the limit values.